The present invention is directed to a machine for the processing of plate-like workpieces, in particular sheet metal, which have a machine frame, a worktable, and a guidance system for moving the workpiece thereabout.
Generally, modern punch presses and like stamping machines have a work table and at least one processing station. A coordinate guide moves the workpiece over the work table parallel to the plane of the work table in two coordinate directions extending perpendicular to each other. This includes a guide rail mounted on the machine frame and movable in the one coordinate direction, and the rail carries at least one workpiece support movable in the other coordinate direction.
In German patent publication DE-A-22 64 852 a revolving punch press is shown in which a machine base with a work table has a guide rail upon which there is mounted a cross-sliding carriage holding the workpiece to be processed. This guide rail is movable in a coordinate direction parallel to the plane of the work table. The cross-sliding carriage at the same time is movable on the guide rail in its longitudinal direction and is consequently movable crosswise to the direction of the sliding of the guide rail. The guide rail and cross-sliding carriage form the coordinate guide of the previously known machine tool.
In its longitudinal direction the guide rail projects on both sides over the work table on the machine base. The fixed work table on the machine base together with two side tables which are movable with the guide rail and engaged with the overhangs of the guide rail to monide the workpiece support. Sliding guide carriages are used for guiding and supporting of the side tables on the machine base and these carriages are also attached to the guide rail and work together with corresponding guide implements on the machine base. The cross-sliding carriage is movable on the guide rail in its longitudinal direction and has clamps for the firm gripping of the sheet metal workpiece to be processed.
During practical implementation of the machines of the type known from German patent publication DE-A-22 64 852, undesired distortions and displacements of the guide rail have adversely occurred. These manifestations were in particular the result of the inertia of the masses being accelerated with the guide rail during machine operation, for example, the cross-sliding carriage mounted on the guide rail, the workpiece held to the guide rail over the cross-sliding carriage and/or of the side tables fastened to the guide rail including the elements for the guiding and supporting of the side tables on the machine base.
To avoid the described undesired distortions and displacements of the guide rail, machines are presently being used to form a unique type. For the reinforcement of the coordinate guide, machines are being supplied with reinforcing elements as seen in German patent publication DE-A-22 64 852. These elements support the guide rail on the machine frame against distortion and displacement in at least one plane running parallel to the plane of the work table. Supports that run between the overhangs of the guide rail and the machine frame and that are moved together with the guide rail come into use as reinforcing elements. The application of such supports then leads to an enlargement of the mass to be supported on the machine frame and to be accelerated together with the guide rail. This in turn requires an appropriate design of the machine frame with respect to its load-bearing capacity. The necessary reinforcement of the coordinate guide on the machines currently in use connect a relatively large mass and this is added to the relatively large weight of the coordinate guide and thereby the entire machine.
The present invention has aimed to enable an improvement in this regard.